This present invention relates to floor finishing machines and more particularly to an improved floor finishing machine for use with a power rider trailer.
The process of finishing a new floor or refinishing an old floor is well known in the art. The steps necessary to finish or refinish a wooden floor generally include the steps of sanding the floor with successively finer grits of sandpaper or other abrasive material, then screening the floor with a mesh screen as a final abrasion to blend the sanded areas. A wooden floor can then optionally be stained, sealed and finally the surface is buffed or polished.
Powered floor sanders come in several varieties, the three most common being drum, belt and rotary sanders. A drum sander has a cylinder covered with removable sandpaper that is rotated against the floor by means of a motor. A belt sander type of floor sander has a belt of sandpaper held by two cylinders which move the belt against the wooden floor by a motor driving one or both cylinders. The cylinder or cylinders of the drum sander or belt sander rotate about the axis generally parallel to the floor.
Drum and belt sanders are designed for the heavier sanding required when finishing a newly installed floor. Drum and belt sanders must be used with care and generally only in the earlier stages of sanding a floor, when the rougher grits of sandpaper are used. These types of machines tend to gouge and scratch a floor and can""t be used for the finer blending required to finish the floor.
After the sanding is completed the floor must be screened. Screening is a process of moving a fine mesh of abrasive screen across the floor to further blend wood together and make for an even surface. The screen is usually a plastic or fabric that is impregnated with an abrasive material.
The heavier sanding is not required of most floors that need to be refinished. Instead, existing floors are typically only treated to a lighter sanding in order to remove any existing layer of wax or dirt, then screened to lightly score the surface, roughing it up to make it take the next coat.
In the past a third type of sander, a rotary sander pushed by a human user, was used for the final stages of finishing a wooden floor. A rotary sander has one or more disks, each called a pad driver, driven by a motor. In a rotary sander sandpaper or screen mesh is affixed to the pad driver and rotated against the floor, about an axis generally perpendicular to the floor, by a motor. Rotary sanders are not designed to do the heavy abrasion work of the drum or belt sanders, instead they are used with the finer grits of sandpaper or mesh screen to smooth the surface in the final sanding and the screening stages. In all cases a layer of stain or sealant is applied to the prepared surface, then usually buffed and polished thereafter.
Most rotary floor sanders are designed to have the user propel the sander across a floor by pushing and pulling on the sander. Such pushing and pulling by a human user renders the desired degree of control to result in an evenly sanded floor surface. A design having the user push the rotary sander is adequate for smaller jobs but is difficult, tedious and inefficient for larger floors, such as those of gymnasiums.
Drum and belt sanders have previously been used in combination with a propelling vehicle. Such a vehicle is disclosed in Mattson, U.S. Pat. No. 5,033,564, later reissued as RE. 34,822. The disclosure of each of these patents is incorporated herein in its entirety by reference. The sander disclosed by this patent is not used in combination with a rotary sander and cannot be used to screen a floor. This propelling vehicle, hereafter referred to as a power rider trailer, is sold by the Floor Style Company of Hastings, Mich. under the trademark FLOOR MACK(copyright).
New rotary floor finishers and methods of using such finishers have been discovered. The invention provides a new implement for use with a power rider trailer, a rotary floor finisher having many advantages.
The new rotary floor finisher allows a human to ride atop the power rider trailer while steering both the power rider trailer and the floor finisher together with a steering system incorporated into the floor finisher. The rotary sander can be used for finish sanding as well as screening.
A rotary sander in combination with a power rider trailer for sanding and screening is therefore highly advantageous for larger floor areas. Importantly, it has been found that rotary sanders coupled to power rider trailers in accordance with the patent incorporated results in a finished floor surface which is as evenly sanded and is as acceptable or identical to a floor surface treated with a rotary sander pushed and pulled directly by a human user. It is estimated that two to three times the floor area can be sanded or screened in a given time period by using a rotary sander/screener in combination with a power rider trailer, instead of using the existing push-driven models.
In one broad aspect the floor finisher is comprised of one or more motors mounted on a housing, the drive shaft of the motor or motors being vertical. Each motor drives one or more pad drivers against a floor during operation and this orientation orients the pad driver to a generally parallel relation to the floor. A supporting structure is affixed to both the hook-up bracket of the power rider trailer to hold the power rider trailer in a substantially rigid relationship to the floor finisher on a side, as well as to the housing with its motors on a second, preferably opposite side. A power rider trailer by itself has no steering mechanism. The power rider trailer drives the floor finisher across the floor while the user steers the combined unit with a handle connected to a wheel mounted on the supporting structure. The wheel both supports the floor finisher and steers the power rider trailer/floor finisher combination.
The floor finisher is attached in substantially rigid relationship to the power rider trailer. In this way the power rider trailer and the floor finisher act as a single unit is therefore much easier to operate than one that would articulate during use.
In operation each pad driver is covered with an appropriate abrasive material for a particular job, for example sandpaper or another abrasive material for sanding, mesh screen for screening. The abrasive material is attached to the face of the pad driver and contacts the floor with the force of the combined weight of the housing, motor and pad driver pushing downwardly on the material against the floor during operation.
While any type of motor can be used to drive the pad drivers, an electric motor is preferred. Moreover almost all enclosed spaces are equipped with electrical outlets, often 220 volt AC outlets, which is the preferred voltage rating of the motor, being more efficient than a standard 110 volt rated motor.
In the preferred embodiment there is additionally included an electrical switch to turn the motors on and off, as well as to regulate the speed of the pad drivers with multiple settings to adjust the RPMs of the pad driver.
A single motor can be made to drive more than one pad driver by methods well known in the art. For example, multiple pad drivers could be driven by a system of pulleys and belts.
If required, weights may also be placed atop the housing to add ballast to increase the force exerted on the pad driver against the floor. It is advantageous to be able to regulate the amount of force exerted on the abrasive material against the floor because there is an optimal amount of force for a given abrasive material. Additional weight on the pad drivers causes any given abrasive material to cause more abrasion. Too little force on the abrasive material results in an undesirable glazing or burnishing of the floor. This burnishing seals the floor, preventing it from receiving further staining or other sealants.
In the preferred embodiment the supporting structure is attached to the housing by vertical lift members which slide on linear bearings attached to the housing. In this way the housing can be raised and lowered while at the same time always keep the orientation of the plane of the pad drivers and the floor in parallel relation. This avoids the problem of an uneven weight being exerted against the pad driver disk, causing the disk to abrade the floor more on one side of the pad driver than the other, perhaps resulting in a gouge.
A pressure release member can further be incorporated to regulate the amount of pressure that the pad driver exerts on the abrasive material against the floor. The pressure release member pulls the housing and motors upwards away from the floor, raising the housing in a cantilevered fashion on the supporting structure, thereby lessening the force exerted on the abrasive material by the driver pad, housing and motor. In the preferred embodiment the supporting structure includes two vertical members, a left hand lift base and a right hand lift base. In the preferred embodiment a cable controlled by the user pulls the housing upwards. This weight or force reduction is best limited to about fifty percent of the initial combined weight of the motor and housing assembly because to too little weight on the abrasive material will result in the aforementioned glazing and burnishing of the floor.
The pad drivers can be removed from contact with the floor altogether for replacement of the abrasive material on the pad drivers. To change the abrasive material a mechanical lift, a lever, may be incorporated to lift the housing up enough to change the abrasive material. The housing and pad drivers are lifted off the floor in a cantilevered fashion off the supporting structure. In the preferred embodiment the mechanical lift raises the pad drivers about four inches off of the floor.
Sanding and screening operations produce a great amount of dust that is not only a fire hazard and health hazard, but must be meticulously removed before the floor can be stained or a polish coat can be applied. A suction generating assembly, to suction the dust generated by the floor finisher e.g. a vacuum cleaner, is provided. The suction generating assembly is connected to the housing by a dust pipe fitted into the housing just over the pad driver to suction the dust away from the sanding operation.
In the preferred embodiment there are two pad drivers, each driven by an individual 220 Volt AC motor, although any convenient plurality of pad drivers with motors could be used. With two pad drivers the motors may drive the pad drivers in the same torsional direction, both clockwise or both counterclockwise, but they are preferably driven in opposite directions. Having one pad driver driven clockwise and the other counterclockwise at substantially the same RPM counterbalances any left or right pull on the floor finisher during operation that would occur otherwise. This counterbalancing of the two motions likewise gives a better finish to the floor being treated.
The pad drivers are covered with an abrasive material such as sandpaper, Emory paper or metal mesh for example, as appropriate to type of wood and type of abrading that is required for a particular floor finishing. These types of abrasive materials and the appropriate use of them in floor finishing are well known in the art.
When using two motors it is desirable to have both motors switched in tandem to keep them turning at the same RPM while in operation. Multi-speed switches are also desirable to allow different sanding speeds, and therefore the preferred embodiment incorporates a two-speed switch, well known in the art, that allows the motors to be run at either speed or be shut off entirely.
Any feature or combination of features described herein is included within the scope of the present invention provided that the features of any such combination are not mutually inconsistent.
Additional aspects and advantages of the present invention are set forth in the following description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.